Whether falling of an asteroid is guilty of death of dinosaurs?
a subject of “asteroid attack“ are very actively exaggerated Recently on television. On some channels it is possible to observe also special programs with participation of “the famous experts in the matter“. All this quite often generates senseless panic and to absurd strange questions. diligently connect by
With falling of an asteroid also legendary extinction of huge reptiles - the dinosaurs who were once inhabiting our planet. Today, probably, each person knows that dinosaurs died owing to falling of an asteroid, however sometimes between concepts “all know“ and “truly“ a distance of the huge size.
Due to the huge number of pseudo-scientific disputes it is possible to ask a question: whether on the matter in disappearance of dinosaurs the asteroid “is guilty“?
To answer this question, for a start we will try to give the answer to other question: whether led falling of asteroids to Earth to sharp changes as a part of a terrestrial biota during the past eras, since emergence of the highest life?
Intensive meteoric bombing by asteroids of planets of terrestrial group continued long enough, but already in the Proterozoic (about 2 billion years ago) came to naught almost.
Of course, large craters, including Cainozoic age, are available also on the Earth`s surface. As one of examples is widely known the Arizonian meteoric crater with a diameter of 1,2 km and age of 50 thousand years left iron - the nickel meteorite with a diameter about 60 m which faced Earth at a speed about 20 km/s.
From the most modern events the Chelyabinsk meteorite at once “christened“ by some mass media “the American bomb“, an UFO and still a couple of similar names is memorable to all.
Each meteorite which “visited“ ever our planet leaves a specific mark in its history: in the geological layers storing in themselves Earth history iridic anomalies - layers with the content of tens times of iridium increased sometimes come across. Almost all terrestrial iridium is concentrated in a kernel. In its crust it is not enough, but in ferruterous meteorites - relatively there is a lot of. Therefore, if the space body iron or iron - stone structure faces Earth, and energy of blow will be rather big, then the dust released into the atmosphere will be carried by winds everywhere and, having gradually accumulated on a terrestrial surface, will remain in the geological chronicle of Earth in the form of iridic anomaly.
In 1980 - by m to year the American scientist Luis Alvares it was suggested that dinosaurs died as a result of collision of Earth with an asteroid of 10 km in the diameter and weighing about 10 billion tons. Also the suitable crater - Chikksulub on on the peninsula Yucatan was found. Further chain of events: there came long (several years) “the asteroid winter“ with a sharp cold snap, from - for whom (and also from - for shielding of a sunlight the dust which is thrown out as a result of collision) photosynthesis then at first herbivorous dinosaurs from - for lack of food died out, and then and carnivorous stopped.
Not really harmonous picture. Chalk - paleogenovy extinction during which died out including dinosaurs concerned first of all sea inhabitants - in the sea all food pyramid collapsed. Meanwhile, on the land only the last 7 - 8 species of dinosaurs from more than 400 different types known to science died out.
On the land crocodiles also safely survived though, apparently, a crocodile in the frozen pond the goner. By the way, much earlier and more large-scale permsko - Triassic extinction when 90% of sea types died out, was also not followed by mass extinction on the land, and it did not manage to be connected with any huge meteoric crater reliably yet. Undoubtedly, attempts to pick up a suitable crater will continue, and is the strongest this business the people who are poorly imagining of what system crises the ecosystem of Earth without any intervention from the outside is capable will be keen.
Besides, we will ask a question: whether duration of “nuclear winter“ studied on computer models to “asteroid winter“ can be extended? Models of “nuclear winter“ proceed from elimination of the majority of the large cities which all combustible materials turned into soot particles will be released highly into the atmosphere where will remain for a long time.
In case of asteroid blow thrown out there will be not a soot, and dust particles. According to some calculations, dust will accumulate in several weeks, but not years, and the most part of vegetation just will not manage to die. Therefore, herbivorous dinosaurs will also survive. Moreover, recently in the west of the USA paleontologists opened two dinozavrovy faunae which endured blow of an asteroid on several tens of thousands of years. Supporters of “simple and graceful“ an asteroid hypothesis can reflect how these dinosaurs transferred hunger and cold of “asteroid winter“ and why all - eventually died out.
Strictly speaking, there is no convincing confirmation of disappearance from a face of Earth at least one species owing to asteroid blow.
As for extinction of dinosaurs, the question comes to mind: “If Alvares`s asteroid safely missed each other in space with Earth - dinosaurs approximately in the same terms would die out?“ Paleontologists surely answer this question: yes, would die out. As any group of types whose ecological niche ceased to exist becomes extinct.
Apparently, extinction of a sea biota had other reasons, than extinction of dinosaurs, and also falling of the mentioned asteroid, and all these events just more - coincided on time less.